One of three types of tire structural member forming systems shown in FIGS. 5 to 7 is used for forming an annular tire structural member of an automotive tire by winding a band-shaped member of a predetermined length around a forming drum and bonding together the leading and the trailing end of the band-shaped member.
The first tire structural member forming system shown in FIG. 5 carries a band-shaped member 01 by a conveyor belt 03 to feed the band-shaped member 01 to a forming drum 02 disposed close to the delivery end of the conveyor belt 03. The belt-shaped member 01 is wound around the forming drum 02 from its leading edge.
The second tire structural member forming system shown in FIG. 6 places a band-shaped member 01 on a flat plate 05 and moves the flat plate 05 supporting the band-shaped member 01 horizontally to bring the band-shaped member 01 close to a rotating forming drum 02. Then, the band-shaped member 01 is wound from its leading edge around the rotating forming drum 02.
The third tire structural member forming system shown in FIG. 7 carries a band-shaped member 01 of a predetermined length by robot hands 07 and 08. The robot hands 07 and 08 hold the band-shaped member 01 at the leading end and at the trailing end, respectively, by gripping or by suction and carry the band-shaped member 01 to a forming drum 02. The robot hand 07 releases the leading end of the band-shaped member 01 at a position corresponding to the circumference of the forming drum 02. Then, the forming drum 02 is rotated and the other robot hand 08 is moved as the band-shaped member 01 is wound around the forming drum 02.
When the band-shaped member 01 is carried by the first tire structural member forming system using the conveyor belt 03 as shown in FIG. 5, the conveyor belt 03 meanders. Therefore, it is possible that the band-shaped member 01 cannot be correctly located (centered) relative to the forming drum 02. When the band-shaped member 01 of a predetermined length is built by successively superposing and bonding together strips obtained by cutting a long band in the predetermined length on the conveyor belt 03 with their edges trued up, the strips cannot be accurately bonded together because the feed rate of the conveyor belt 03 varies.
When the band-shaped member 01 is carried by the second tire structural member forming system using the flat plate 05 as shown in FIG. 6, the band-shaped member 01 can be set correctly. However, the long flat plate 05 needs to be moved horizontally by a distance nearly equal to its length. Therefore, a large space must be secured for the flat plate 05 to move horizontally and hence the second tire structural member forming system is unsatisfactory in space efficiency.
Although the robot hands 07 and 08 used by the third tire structural member forming system as shown in FIG. 7 are capable of accurately setting the band-shaped member 01 relative to the forming drum 02, the third tire structural member forming system is complicated.
The present invention has been made in view of the foregoing problems and it is therefore an object of the present invention to provide a tire structural member forming method capable of accurately setting a band-shaped member of a predetermined length on a forming drum, of efficiently using space and of forming the tire structural member at a low cost by a simple mechanism.